Lumen reentry devices and methods

ABSTRACT

A device, such as for use with lumen reentry, including a catheter including a balloon disposed at a distal end thereof, the catheter being formed with a first lumen through the balloon for passing therethrough a guidewire and a second lumen for inflation and deflation of the balloon, the catheter and the balloon being sized and shaped for entry between two layers of a wall of a body lumen, wherein upon expansion of the balloon when placed between the layers, a distal portion of the first lumen that passes through the balloon is bent with respect to a portion of the first lumen proximal to the balloon and is directed towards the body lumen.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 USC §119 to U.S. ProvisionalPatent Application 60/920,561, filed Mar. 29, 2007, U.S. ProvisionalPatent Application 60/994,732, filed Sep. 24, 2007, and U.S. ProvisionalPatent Application 60/997,099, filed Oct. 2, 2007, the disclosures ofwhich are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to devices and methods forreentry from one lumen into another lumen, such as but not limited to,reentry into a true lumen of a blood vessel from the extraluminal orsub-intimal space of the vessel.

BACKGROUND OF THE INVENTION

Chronic Total Occlusion (CTO) is an arterial vessel blockage (typicallyof plaque) that obstructs blood flow. CTO can occur both in coronary andperipheral arteries, and generally results from the same underlyingcause—atherosclerosis.

One of the main difficulties in crossing a total occlusion is that theclinician does not know exactly how hard the plaque is until steering aguidewire to the occlusion. If the occlusion is relatively new, theplaque is likely to be soft enough and the guidewire may penetrate theplaque. However, after several weeks or months, the occlusion becomesfibrotic and calcified and the plaque becomes much harder, renderingguidewire crossing of the occlusion difficult if not impossible. Failureto cross the obstruction is the primary failure mode for CTOrecanalization.

Another problem is that the CTO blocks contrast agents from flowingthrough the artery past the obstruction, preventing use of fluoroscopyto guide the guidewire. This increases the risk of perforating ordissecting the vessel, and may possibly increase the risk oftamponade—blood leaking out of the artery around the heart or peripheralorgan. Even crossing a partially occluded blood vessel, especially longand curved occlusions, can be difficult and time consuming.

As is well known in anatomy, arteries generally have three coats orlayers: an internal or endothelial coat (tunica intima of Kölliker); amiddle or muscular coat (tunica media); and an external orconnective-tissue coat (tunica adventitia). The two inner coats togetherare easily separated from the external adventitial layer, and the twoinner coats are sometimes referred together as the intimal layer ratherthan the medial and intimal layers. It is known in the art that duringan attempt to get past an occlusion with a guidewire, the guidewiresometimes inadvertently penetrates into the subintimal space between theintimal layer and the adventitial layer of the blood vessel as itattempts to cross the occlusion. Once in the subintimal space, it isvery difficult and in many cases impossible to direct the guidewire backinto the blood vessel true lumen beyond the occlusion.

However, techniques have been developed for entering the subintimalspace on purpose and reentering the true lumen after the occlusion. Thisso-called subintimal recanalization can be a useful procedure,especially when using drug eluting stents, and is widely used. One ofthe advantages of subintimal recanalization is that a dissection of thesubintimal space is more likely to produce a smooth lumen and improvedblood flow than a lumen produced by plowing through calcified plaque.However, technical failure occurs in about 30% of patients undergoingpercutaneous intentional extraluminal recanalization, mostly due to theinability to reenter the distal true lumen.

If during percutaneous extraluminal recanalization, the true lumencannot be reentered with guidewire manipulation, a true lumen reentrydevice must be used. Currently there are two specially designed reentrydevices in the market.

The pioneer reentry catheter (from Medtronic, Santa Rosa, Calif., US) isa 7 Fr. intravascular ultrasound (IVUS) device that is placed in thedissection beyond the occlusion. The IVUS image provides an image of thevessel wall. The catheter is constructed with a monorail lumen fordelivery of the device over a 0.014 inch wire, and a second wire lumenthrough the end of the catheter, which ends in a curved nitinol needlethat can retract into the catheter near the distal end. The needle isdeployed by sliding it out of a distal port at the side of the catheterjust proximal to the IVUS transducer. The IVUS device is used toultrasonically guide, turn and manipulate the curved needle to arrive atthe correct radial orientation for reentry into the true lumen.

The Outback LTD reentry catheter (Cordis, Miami Lakes, Fla., US) is a 6Fr. catheter with a retractable nitinol curved needle at the distal end.The needle is straight when withdrawn in the catheter. When pushedforward, the needle is restored to its curved shape and can penetratethe medial and intimal layers to reenter the true lumen. The rotationalorientation of needle deployment is provided by fluoroscopic guidingmarkers on the catheter.

SUMMARY OF THE INVENTION

The present invention seeks to provide novel devices and methods forlumen reentry, as is described more in detail hereinbelow.

The present invention has many applications, such as but not limited to,true lumen reentry in PTA (percutaneous transluminal angioplasty), PTCA(percutaneous transluminal coronary angioplasty), and any otherpercutaneous or non-percutaneous placement of a catheter between twoadjacent layers of vessels, arteries, soft tissue, or any other humantissue.

In one embodiment of the invention, a device and method are provided forreentry into a true lumen of a blood vessel from the extraluminal orsub-intimal space of the vessel. The invention eliminates the need forrotational direction by an imaging system or for curved needles as inthe prior art. Instead, in one embodiment of the invention that includesa catheter and guidewire, the lumen reentry device automatically bendsthe catheter after the occlusion so that the catheter distal end isdirected in the direction of the true lumen so that the guidewire canpenetrate back into the true lumen.

The invention assists the clinician (e.g., cardiologist, radiologist,vascular surgeons or any other medical doctor who engages in angioplastyprocedures) in treating total occlusions, and can be used to cross bothnew and soft plaque and old and hard plaque.

In one non-limiting embodiment of the invention, the method includes 1)inserting a guidewire in a balloon catheter into the proximal vesseltrue lumen, 2) dissecting the vessel with the guidewire near theproximal end of the occlusion, 3) moving the guidewire through thesubintimal space of the blood vessel distally past the occlusion, 4)moving the balloon catheter distally past the occlusion over theguidewire, 5) moving the guidewire proximally to the balloon, anddeploying (inflating) a balloon that deflects the intimal layer awayfrom the adventitial layer of the blood vessel and bends the cathetertowards the inner volume of the true lumen; and 6) penetrating theintimal layer back into the true lumen and reentering the true lumenwith the guidewire. The method may further include performing balloonangioplasty through the recanalized lumen, and deploying a stent. Thestent is typically long enough to start in the proximal true lumen andend in the distal true lumen.

There is provided in accordance with an embodiment of the invention alumen reentry device including a catheter including a balloon disposedat a distal end thereof, the catheter being formed with a first lumenthrough the balloon for passing therethrough a guidewire and a secondlumen for inflation and deflation of the balloon, the catheter and theballoon being sized and shaped for entry between two layers of a wall ofa body lumen, wherein upon expansion of the balloon when placed betweenthe layers, a distal portion of the first lumen that passes through theballoon is bent with respect to a portion of the first lumen proximal tothe balloon and is directed towards the body lumen. The balloon mayinclude an inverted distal neck.

In one non-limiting embodiment of the invention, a guidewire passesthrough the first lumen and is adapted to pierce at least one of thelayers to enter the body lumen. It is noted that the “guidewire”piercing the layer or layers encompasses not just the guidewire but anystylet, needle or wire capable of puncturing through to the lumen.

In another non-limiting embodiment of the invention, a hypo-tube needleis disposed in the first lumen and a guidewire passes through aninternal cavity of the needle, a distal end of the needle being adaptedto pierce at least one of the layers to enter the body lumen.

In one non-limiting embodiment of the invention, a diameter of theballoon is not more than a diameter of the body lumen.

In one non-limiting embodiment of the invention, a length of the balloonis not more than the diameter of the balloon. Alternatively, the lengthof the balloon can be double the diameter of the balloon. Other lengthsare also possible.

In one non-limiting embodiment of the invention, the catheter is formedwith a pivoting portion proximal to the distal portion upon which theballoon is disposed. The pivoting portion may include a weakened sectionhaving a smaller wall thickness than other portions of the catheter.Alternatively, the pivoting portion includes a portion made of aflexible material. Alternatively, the pivoting portion includes a joint.Alternatively, the pivoting portion includes a section which is softerand easier to bend than the rest of the catheter.

In one non-limiting embodiment of the invention, the catheter isslidingly disposed in a sheath and the distal portion of the catheter isbendable at a juncture with a distal end of the sheath.

In one non-limiting embodiment of the invention, a diameter of theballoon is equal to or slightly larger than a diameter of the bodylumen.

In one non-limiting embodiment of the invention, the device furtherincludes a second balloon mounted on the catheter proximal to theballoon, the second balloon being inflatable through a third lumenformed in the catheter.

It is noted that the invention is not limited in the number of balloonsand lumens. For example, the device can include four lumens (two forinflating balloons, one for passing a guidewire, and another one forinjecting a contrast agent). Another example is a three lumen device(one for inflating a balloon, one for passing a guidewire, and one forinjecting a contrast agent).

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully fromthe following detailed description, taken in conjunction with thedrawings in which:

FIG. 1 is a simplified, partially sectional, schematic illustration of alumen reentry device, constructed and operative in accordance with anembodiment of the present invention;

FIG. 2 is another simplified, partially sectional, schematicillustration of the lumen reentry device of FIG. 1, including ahypo-tube needle disposed in a catheter;

FIGS. 3 and 4 are simplified, partially sectional, schematicillustrations of the lumen reentry device of FIG. 1 introduced in ablood vessel subintimal space, in accordance with an embodiment of thepresent invention, respectively before and after balloon inflation;

FIG. 5 is a simplified, partially sectional, schematic illustration of alumen reentry device with a covering sheath, constructed and operativein accordance with another embodiment of the present invention;

FIG. 6 is a simplified, partially sectional, schematic illustration ofthe lumen reentry device of FIG. 5 introduced in the subintimal space ofa blood vessel, with a hypo-tube penetrating through the internal bloodvessel wall layer, after moving the covering sheath proximally backwardsand after balloon inflation;

FIGS. 7A and 7B are simplified schematic illustrations of a non-inverteddistal balloon neck (FIG. 7A) and a balloon with such a neck mounted ona catheter (FIG. 7B);

FIGS. 7C and 7D are simplified schematic illustrations of an inverteddistal balloon neck (FIG. 7C) and a balloon with such a neck mounted ona catheter (FIG. 7D), in accordance with an embodiment of the presentinvention;

FIG. 8 is a simplified, partially sectional, schematic illustration of alumen reentry device in the subintimal space of a blood vessel afterballoon inflation, showing that if the balloon has a protruded,non-inverted distal neck it may fail to orient the device properly forpuncturing the blood vessel for reentry into the true lumen;

FIG. 9 is a simplified, partially sectional, schematic illustration of alumen reentry device, constructed and operative in accordance with yetanother embodiment of the present invention, introduced in thesubintimal space of a blood vessel, using a long angioplasty balloonhaving an inverted distal neck and no neck distal protrusion;

FIG. 10 is a simplified, partially sectional, schematic illustration ofa lumen reentry device, constructed and operative in accordance withstill another embodiment of the present invention, and including areentry balloon and a PTA balloon on the same catheter; and

FIG. 11 is a simplified, partially sectional, schematic illustration ofthe lumen reentry device of FIG. 10 introduced in the subintimal spaceof a blood vessel, and after balloon inflation.

DETAILED DESCRIPTION OF EMBODIMENTS

Reference is now made to FIG. 1, which illustrates a lumen reentrydevice 1, constructed and operative in accordance with an embodiment ofthe present invention. Device 1 includes a catheter 10 which has aballoon 11 disposed at a distal end thereof. The distal end of catheter10 protrudes only slightly, or does not protrude at all, beyond balloon11. The significance of this will be explained further below. Catheter10 is formed with a first lumen 12 through balloon 11 for passingtherethrough a guidewire 27, and a second lumen 13 for inflation anddeflation of balloon 11.

Catheter 10 may be fabricated from polyethylene, polyurethane, PEBAX(polyether block amide from Arkema), nylon or other polymers known inthe art. The catheter shaft can also be made from polymers reinforcedwith metal wires braid or springs, as is known in the art.

Balloon 11 may be fabricated from polyurethane, silicon, PET(polyethylene terephthalate), and other suitable polymers known in theart.

Reference is now made to FIG. 3, which illustrates lumen reentry device1 introduced in a true lumen 8 and then through a dissection 2,typically between an internal intimal layer 3 (perhaps both the mediallayer together with the intimal layer) and an external adventitial layer4 of a blood vessel 5, over a guidewire 27 (shown for clarity only atthe proximal end of catheter 10). Balloon 11 has been passed beyond thedistal end of an occlusion 6.

In the illustrated embodiment, balloon 11 is a small conical balloon.The balloon diameter is preferably similar or smaller than the diameterof the true lumen 8 of blood vessel 5. Balloon 11 can also have a roundball (spherical) shape or other similar elliptical shapes, wherein itsdiameter is a few times the diameter of catheter 10, but not more thanthe diameter of true lumen 8. In the illustrated embodiment, the lengthof balloon 11 is relative short compared to common angioplasty balloons,usually not more than twice its diameter.

When catheter 10 and balloon 11 are in place as shown in FIG. 3, balloon11 is then inflated, e.g., to a pressure of several atmospheres, asshown in FIG. 4. The balloon inflation creates a space 7 (void orpassageway) by pushing the surrounding tissues, that is, intimal layer 3and external adventitial layer 4. Balloon 11 is located subintimallybetween layers 3 and 4, and the high pressure inflation produces arelatively high force on the two tissue layers 3 and 4. The forces causethe internal intimal layer 3 to yield first, bending or folding towardsthe adjacent true lumen 8, rather than causing the external adventitiallayer 4 to stretch or become extended. This is because the force neededto stretch the tougher external adventitial layer 4 is much higher thanthe force needed to fold or bend the more flexible internal intimallayer 3, especially since the internal intimal layer 3 is folding towardthe true lumen 8.

Folding of the internal intimal layer 3, with minimal or no movementfrom the external adventitial layer 4, causes the distal end of catheter10 to bend towards the true lumen 8. This automatically points thedistal end of catheter 10 and guidewire 27 (shown also at the distal endof catheter 10 in FIG. 4) correctly towards the true lumen 8 forpunching back through the internal intimal layer 3 into the true lumen8, without any need for an imaging system for rotational orientation.

The penetration into the true lumen 8 through the internal blood vessellayer 3 can be done simply and directly with guidewire 27. Afterwardscatheter 10 can be withdrawn from the patient to leave guidewire 27 inplace, such as for placing a stent (not shown). It is noted that thesame guidewire 27 can be used for catheter 10 and for introducing thestent, which significantly facilitates the clinician's work.

Reference is now made to FIG. 2, which illustrates an alternative way ofpuncturing the internal layer 3 for reentry into the true lumen 8. Inthis embodiment, a flexible hypo-tube needle 14 is disposed in firstlumen 12 of catheter 10. Hypo tube 14, preferably made from a shapememory alloy such as nitinol, may be pre-cut to a needle shape at itsdistal end 15.

The embodiment of FIG. 2 is used the same way as the embodiment of FIG.1, except that in the embodiment of FIG. 2, after balloon inflation,hypo-tube needle 14 is used to puncture internal intimal layer 3 topenetrate back into the true lumen 8. Guidewire 27 may then beintroduced through an internal cavity 16 of needle 14 into the truelumen 8. Afterwards needle 14 may be retracted into catheter 10, andcatheter 10 may be withdrawn from the patient, leaving guidewire 27 inplace, as described above. The bending angle is a function of thecatheter point of bending at the plaque distal end and the balloondiameter

As mentioned above, the distal end of catheter 10 protrudes onlyslightly, or does not protrude at all, beyond balloon 11. Thesignificance of this is now explained with reference to FIGS. 7A-8.

FIGS. 7A and 7B illustrate a balloon having a balloon body 11A andnon-inverted distal and proximal necks 11B and 11C, respectively. FIG.7B shows such a balloon mounted on catheter 10.

In contrast, FIGS. 7C and 7D illustrate the balloon 11 of the presentinvention with distal and proximal necks 11D and 11E, respectively.Distal neck 11D is inverted into the inner space of balloon 11. Theinverse or inverted distal neck 11D of balloon 11 can be manufactureddirectly as an inverted neck or can be made non-inverted and theninverted before bonding to catheter 10. Proximal neck 11E can be madeand bonded in a standard way.

Reference is now made to FIG. 8, which illustrates the lumen reentrydevice with a balloon having the non-inverted distal neck 11A in thesubintimal space of a blood vessel after balloon inflation. It is seenthat the non-inverted distal neck 11A can bend and point away from thetrue lumen 8, thereby failing to orient the device properly forpuncturing the blood vessel for reentry into the true lumen 8.

Reference is made again to FIG. 4. In another embodiment of the presentinvention, catheter 10 may be formed with a pivoting portion 18 proximalto a distal portion 26 of catheter 10 upon which balloon 11 is disposed.Pivoting portion 18 may be formed in several ways. For example, pivotingportion 18 may comprise a weakened section having a smaller wallthickness, or a portion made of a flexible material, or a joint, or asection without metal wires, springs or braids, making it softer andeasy to bend or rotate with minimal resistance from the rest of thecatheter shaft. The position of pivoting portion 18, together with theballoon diameter, defines the catheter distal end bend angle.

Reference is now made to FIGS. 5 and 6, which illustrate lumen reentrydevice 1 with a covering sheath 17, constructed and operative inaccordance with another embodiment of the present invention. Sheath 17may be fabricated from polyurethane, PET, PTFE or other suitablepolymers known in the art. As seen in FIG. 6, catheter 10 and sheath 17are inserted together over guidewire 27. After being placed distallybeyond occlusion 6, sheath 17 can be pulled slightly backwards(proximally) to a pre-determined distance and distal portion 26 ofcatheter 10 bends at the juncture with the distal end of sheath 17. Thebending angle is a function of the catheter point of bending at thesheath distal end and the balloon diameter.

Reference is now made to FIG. 9, which illustrates a lumen reentrydevice, constructed and operative in accordance with yet anotherembodiment of the present invention. In this embodiment, a long balloon20, similar to balloons used in angioplasty procedures, but havinginverted distal neck 20A as described before, can be used for reentry.Proximal neck 20B can be non-inverted as described before. If thediameter of balloon 20 is equal to or slightly larger than the bloodvessel internal diameter, expansion of balloon 20 forces the internallayer 3 to fully collapse towards the opposite blood vessel wall. Aguidewire or straight needle can then be used to punch the blood vesselinternal layer 3 into the true lumen 8, as described above. Pivotingportion 18 of catheter 10 can be used proximally to balloon 20 to allowrotating or bending balloon 20.

Reference is now made to FIG. 10, which illustrates a lumen reentrydevice 30, constructed and operative in accordance with still anotherembodiment of the present invention.

Device 30 includes a catheter 32 which has a balloon 34 disposed at adistal end thereof. The distal end of catheter 32 protrudes onlyslightly, or does not protrude at all, beyond balloon 34, as in theprevious embodiments. Accordingly the distal neck of balloon 34 isinverted. Catheter 32 includes an external tube 33 in which an internaltube 35 is disposed. The distal neck of balloon 34 may be bonded orotherwise attached to internal tube 35, and its proximal neck toexternal tube 33. Internal tube 35 is smaller, and preferably softer ormore flexible than external tube 33, thereby creating a pivotal pointfor balloon 34 to bend when inflated. Internal tube 35 is formed with afirst lumen 36 for passing therethrough a guidewire 37. A second lumen38 is formed between the internal and external tubes 35 and 33 forinflation and deflation of balloon 34.

Balloon 34 is a reentry balloon and its use is as described above. Inaddition, proximal to balloon 34, a second balloon 40 is mounted on thesame catheter 32. Second balloon 40 is a PTA balloon and may be attachedto the external tube 33 of catheter 32 with regular, non-inverted necks.Second balloon 40 may be inflated or deflated via a third lumen 42formed in the external tube 33 of catheter 32.

Reference is now made to FIG. 11, which illustrates lumen reentry device30 introduced in the subintimal space of a blood vessel, and afterballoon inflation. The conical shape of balloon 34 helps direct thedistal end of catheter 32 towards the true lumen. The second balloon 40may then be inflated for angioplasty and stent introduction procedures.

Other variations of the embodiment of device 30 are in the scope of theinvention. For example, the device may include two lumens (one for theguidewire and another for the balloon), wherein the balloon lumen caninflate either two separate balloons (PTA and reentry) or one balloonthat has two sub-balloons (two “humps”), one for PTA and the other forreentry.

It will be appreciated by persons skilled in the art that the presentinvention is not limited by what has been particularly shown anddescribed hereinabove. Rather the scope of the present inventionincludes both combinations and subcombinations of the features describedhereinabove as well as modifications and variations thereof which wouldoccur to a person of skill in the art upon reading the foregoingdescription and which are not in the prior art.

1. A device comprising: a catheter comprising a balloon disposed at adistal end thereof, said catheter being formed with a first lumenthrough said balloon for passing therethrough a guidewire and a secondlumen for inflation and deflation of said balloon, said catheter andsaid balloon being sized and shaped for entry between two layers of awall of a body lumen, wherein upon expansion of said balloon when placedbetween said layers, a distal portion of said first lumen that passesthrough said balloon is bent with respect to a portion of said firstlumen proximal to said balloon and is directed towards said body lumen.2. The device according to claim 1, wherein said balloon comprises aninverted distal neck.
 3. The device according to claim 1, furthercomprising a guidewire that passes through said first lumen and which isadapted to pierce at least one of the layers to enter said body lumen.4. The device according to claim 1, further comprising a hypo-tubeneedle disposed in said first lumen and a guidewire that passes throughan internal cavity of said needle, a distal end of said needle beingadapted to pierce at least one of the layers to enter said body lumen.5. The device according to claim 1, wherein a diameter of said balloonis not more than a diameter of said body lumen.
 6. The device accordingto claim 1, wherein a length of said balloon is not more than a diameterof said balloon.
 7. The device according to claim 1, wherein saidcatheter is formed with a pivoting portion proximal to the distalportion upon which said balloon is disposed.
 8. The device according toclaim 7, wherein said pivoting portion comprises a weakened sectionhaving a smaller wall thickness than other portions of said catheter. 9.The device according to claim 7, wherein said pivoting portion comprisesa portion made of a flexible material.
 10. The device according to claim7, wherein said pivoting portion comprises a joint.
 11. The deviceaccording to claim 7, wherein said pivoting portion comprises a sectionwhich is softer and easier to bend than the rest of said catheter. 12.The device according to claim 1, wherein said catheter is slidinglydisposed in a sheath and the distal portion of said catheter is bendableat a juncture with a distal end of said sheath.
 13. The device accordingto claim 1, wherein a diameter of said balloon is equal to or slightlylarger than a diameter of said body lumen.
 14. The device according toclaim 1, further comprising a second balloon mounted on said catheterproximal to said balloon, said second balloon being inflatable through athird lumen formed in said catheter.